X-ray fluorescence (XRF) is a nondestructive, multielemental, fast and cost-effective analysis technique. It can be applied in a nonvacuum environment directly on the samples without any preparation. As ... [more ▼]

X-ray fluorescence (XRF) is a nondestructive, multielemental, fast and cost-effective analysis technique. It can be applied in a nonvacuum environment directly on the samples without any preparation. As archaeological and historical objects are often unique and may not be easily movable, a mobile XRF detector system allowing in situ analysis is ideally suited for archaeometric applications. A mobile system was designed and built at the IPNAS laboratory to provide such analyses. The system includes an industrial grade x-ray generator which supplies the primary x-ray beam, an air-cooled silicon rift Detector detector (SDD) with a 5-mm(2) active area. The data acquisition system measures the energy and the intensity of the secondary fluorescence x-rays. The detector signal is amplified and analyzed by a multichannel recorder coupled to a microcomputer running JavaSpectre which visualizes and analyzes spectra obtained from the detector. The detection head, containing the detector, the x-ray tube and its power supply, are fixed on a movable platform allowing independent vertical and horizontal movement. All displacements are controlled by a hand-held personal digital assistant (PDA) (Palm) which exchanges data with microcontrollers embedded in the system providing a very precise positioning of the detector over a surface of many square meters. This system control, as well as a typical application of this XRF spectrometer for analyzing pigment composition of a wall painting, will be described. Copyright (C) 2008 John Wiley & Sons, Ltd. [less ▲]

Radiative lifetimes have been calculated for 15 levels of Xe VII belonging to the configurations 5s5p, 5p(2), 5s5d, 5s6s, 5p5d, 4f5p, 5p5d and 5s5f and for 4 levels of the 5p and 5d configurations of Xe ... [more ▼]

Radiative lifetimes have been calculated for 15 levels of Xe VII belonging to the configurations 5s5p, 5p(2), 5s5d, 5s6s, 5p5d, 4f5p, 5p5d and 5s5f and for 4 levels of the 5p and 5d configurations of Xe VIII. A relativistic Hartree-Fock approach including core-polarization effects, on the one hand, and a purely relativistic multiconfiguration Dirac-Fock method, on the other hand, have been used for the calculations. The accuracy of the present set of results has been assessed through comparisons with radiative lifetime measurements obtained by beam-foil spectroscopy. A good agreement between theory and experiment is observed for most of the levels. A new set of transition probabilities is proposed for 169 transitions of Xe VII and 45 transitions of Xe VIII. [less ▲]

A handheld x-ray spectrometer has been realized and tested. The purpose of the device is to measure the thickness of coated samples in the range of 1-1500 nm in an industrial environment. Accuracy of ... [more ▼]

A handheld x-ray spectrometer has been realized and tested. The purpose of the device is to measure the thickness of coated samples in the range of 1-1500 nm in an industrial environment. Accuracy of similar to 3% has been achieved in this range with a measurement time of 1 min. Automated software has been implemented to allow utilization by a nonspecialist operator. An automated calibration procedure, based on measurements of reference samples, is used. (C) 2007 American Institute of Physics. [less ▲]

Oscillator strengths have been calculated for the transitions depopulating levels of the 3s(2)3p(3), 3s3p(4) configurations of K V, of the 3s(2)3p(2), 3s3p(3) configurations of K VI and of the 3s(2)3p ... [more ▼]

Oscillator strengths have been calculated for the transitions depopulating levels of the 3s(2)3p(3), 3s3p(4) configurations of K V, of the 3s(2)3p(2), 3s3p(3) configurations of K VI and of the 3s(2)3p, 3s3p(2), 3p(3) and 3s3p3d configurations of K VII. A multiconfiguration Dirac-Fock method, incorporating the relativistic two-body Breit interaction and quantum electrodynamics corrections due to self-energy and vacuum polarization, has been used for the calculations. The reliability of this approach has been tested by comparison with relativistic Hartree-Fock calculations and also with some experimental measurements performed by beam-foil spectroscopy at a beam energy of 1.7 MeV. [less ▲]

For several years, the specific features of PIXE and PIGE have made them very attractive in the field of archaeometry. Among them, non-destructivity is one of the most important. The possibility of ... [more ▼]

For several years, the specific features of PIXE and PIGE have made them very attractive in the field of archaeometry. Among them, non-destructivity is one of the most important. The possibility of working under atmospheric pressure is also important because of the very different shapes and sizes of the artefacts concerned. However, these ion beam techniques suffer from the same disadvantage: the information coming from x-rays or),brays produced at different places along the charged particle path is integrated. That prevents one from taking into account the possible element concentration gradients due to multilayered systems or diffusion processes. This paper presents several applications of PIXE and PIGE applied under variable ion beam incident angle. PIGE has been mainly used for studying ancient glass items or glass windows in order to detect or evaluate the glass corrosion process. The examples given for PIGE deal with Roman and Merovingian glass objects and cathedral glass windows and PIXE applications concern studies for resolving the multilayered structure of easel paintings. The set-up allowing one to perform the measurements should be very stable, the rotation axis should pass through the beam axis and the detector should follow the sample movement. Copyright (c) 2005 John Wiley [less ▲]

We present observations of VUV transitions between doubly excited sextet states in O, IV, F V and Ne VI. Spectra were produced by collisions of an O+, (FH)(+) and Ne+ beam with a thin carbon foil target ... [more ▼]

We present observations of VUV transitions between doubly excited sextet states in O, IV, F V and Ne VI. Spectra were produced by collisions of an O+, (FH)(+) and Ne+ beam with a thin carbon foil target. Some observed lines are assigned to the 1s2s2p(2)3p L-6-1 s2p(3)3p P-6 electric-dipole transitions in 0 IV, F V and Ne VI, and are compared with the results of multi-configuration Hartree-Fock (with QED and higher-order corrections) and multi-configuration Dirac-Fock calculations. 31 new lines have been identified. The sextet systems of boronlike ions are possible candidates for x-ray and VUV lasers. [less ▲]

Radiative lifetime measurements were performed with time-resolved laser-induced fluorescence techniques for 47 levels of the astrophysically important ion Sm1+ over the energy range 21000-36 000 cm(-1 ... [more ▼]

Radiative lifetime measurements were performed with time-resolved laser-induced fluorescence techniques for 47 levels of the astrophysically important ion Sm1+ over the energy range 21000-36 000 cm(-1). The new results have been compared with previous measurements but also with theoretical calculations taking configuration interactions and core-polarization effects into account, and a satisfying agreement has been found for many levels of this complex ion. New calculated transition probabilities are deduced from the experimental lifetimes and from the theoretical branching fractions for 162 transitions of astrophysical interest. These results will help astrophysicists in the quantitative investigation of the chemical composition of CP stars. [less ▲]

The hyperfine structure of 40 levels of neutral manganese has been studied by means of Fourier transform emission spectroscopy. The light source was a home-made 99.5% pure manganese hollow-cathode lamp ... [more ▼]

The hyperfine structure of 40 levels of neutral manganese has been studied by means of Fourier transform emission spectroscopy. The light source was a home-made 99.5% pure manganese hollow-cathode lamp. From the analysis of the line profiles observed in the visible and infrared regions, we have been able to deduce new magnetic dipole constants for 18 levels and to revise previous results for 22 additional levels. [less ▲]

Radiative lifetimes of 6 levels belonging to the 4f(5)((6)Hdegrees, (6)Fdegrees)5d configuration of Sm III have been measured for the first time using a time-resolved laser-induced fluorescence technique ... [more ▼]

Radiative lifetimes of 6 levels belonging to the 4f(5)((6)Hdegrees, (6)Fdegrees)5d configuration of Sm III have been measured for the first time using a time-resolved laser-induced fluorescence technique. Experimental data have been compared with semi-empirical calculations. The agreement is excellent for 4 levels with (6)Fdegrees as a parent term. Larger discrepancies (53 and 37%) are observed for 2 levels with (6)Hdegrees and (6)Fdegrees, respectively, as a parent term and are explainable by strong mixing and cancellation effects occurring in the line strength calculations which are responsible of "instabilities" occurring in the lifetimes considered as a function of J value within the term. Branching ratios for the lines depopulating the levels of interest have been measured by Fourier transform spectroscopy. A first set of oscillator strengths has been deduced for this ion. [less ▲]

The energies and lifetimes of doubly excited sextet states of boron-like O IV, F V, and Ne VI are calculated with the multiconfiguration Hartree-Fock approach, including QED and higher-order corrections ... [more ▼]

The energies and lifetimes of doubly excited sextet states of boron-like O IV, F V, and Ne VI are calculated with the multiconfiguration Hartree-Fock approach, including QED and higher-order corrections, and also with the multiconfiguration Dirac-Fock GRASP code. The wavelengths and transition rates of electric-dipole transitions from the inner-shell excited terms 1s2s2p23s 6P–1s2p33s 6So are investigated by beam-foil spectroscopy in the XUV spectral region. The predicted transition wavelengths agree with the experiment. The higherorder corrections, fine structures, and spectrum with high wavelength resolution are found to be critically important in these comparisons. Nine new lines have been identified. The ground sextet states of boronlike atoms are metastable and well above several ionization levels. These are possible candidates for XUV and soft x-ray lasers. [less ▲]

The particle induced X-ray emission method is perfectly adapted to the study, by external beam, of art objects (like paintings) and allows non-destructive analysis of the atomic composition of the target ... [more ▼]

The particle induced X-ray emission method is perfectly adapted to the study, by external beam, of art objects (like paintings) and allows non-destructive analysis of the atomic composition of the target. However, a strange phenomenon occurs during irradiation on some pigments: dark brownish stains appear, and this could be due to the formation of color centers. In fact, these darkening spots progressively fade out and disappear after a few weeks. Heat and UV light accelerate the decreasing process. The aim of this study is to understand the physical processes of the stain creation and to find a way to make stains disappear, avoiding any damage for the painting. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

Lifetimes of four short-lived levels belonging to the 4f(8)(F-7)6p configuration of Tb III have been measured using a two-step excitation time-resolved laser-induced fluorescence technique. They agree ... [more ▼]

Lifetimes of four short-lived levels belonging to the 4f(8)(F-7)6p configuration of Tb III have been measured using a two-step excitation time-resolved laser-induced fluorescence technique. They agree quite well with multiconfigurational relativistic Hartree-Fock calculations performed with inclusion of core-polarization effects. Using the experimental lifetimes and the theoretical branching fractions, a set of transition probabilities has been deduced for this ion. [less ▲]

Although glass is usually considered as a very stable archaeological material, it can undergo severe degradation. Soda-lime glass, the most common glass throughout ancient times, is particularly sensitive ... [more ▼]

Although glass is usually considered as a very stable archaeological material, it can undergo severe degradation. Soda-lime glass, the most common glass throughout ancient times, is particularly sensitive to this problem. The glass surface absorbs moisture from its environment and the contact with CO2 causes Na2O and NaOH to convert to Na2CO3, which is extremely hygroscopic. The subsequent unstable glass layer can be leached out and causes decomposition of the glass. The non-destructive PIGE-PIXE method of investigation allows detection of this phenomenon even if no visible effect appears. The variable incident angle method is able to discern the depth of the degradation. One aim of such studies is the possible dating or at least fake detecting of archaeological materials, Furthermore, even objects of large size can be investigated with the atmospheric PIGE-PIXE Set-LIP, Some examples of measurements on ancient glass are given. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

The rates of several electric-dipole forbidden decays of 3p and 3d levels in Cl-, S-, P- and Si-like ions of Fe have been measured optically at a heavy-ion storage ring. In several cases, more than one ... [more ▼]

The rates of several electric-dipole forbidden decays of 3p and 3d levels in Cl-, S-, P- and Si-like ions of Fe have been measured optically at a heavy-ion storage ring. In several cases, more than one decay contributes to a given decay curve, which complicates the analysis. The lifetime results, with a precision range from 0.6 to 20%, compare well with some theoretical predictions, but are more precise. They are also more precise than some experimental data from an electrostatic ion trap. [less ▲]

We have recorded hollow-cathode spectra of neutral vanadium by Fourier transform spectroscopy in the near infrared - visible region (9000-17 000 cm-1). 36 transitions showing hyperfine structure have been ... [more ▼]

We have recorded hollow-cathode spectra of neutral vanadium by Fourier transform spectroscopy in the near infrared - visible region (9000-17 000 cm-1). 36 transitions showing hyperfine structure have been analyzed, allowing us to deduce magnetic dipole constants for 27 levels belonging to the 3d44p and 3d34s4p configurations. For 22 of these levels no data were previously available. [less ▲]